1. Field of the Invention
This invention relates in general to medical machines for performing surgery and treatment utilizing ultrasonic energy and in particular to a novel ultrasonic operating unit.
2. Description of the Prior Art
Biological effects were achieved accidentally with ultrasound by Langevin who made "fish-kills" around 1922 with military sonar which destroyed tiny fish if they swam into its field. Records show that these tiny particles of tissue were probably captured in a low sonic pressure "well" and that their body cells were over-heated by the beam, causing their death. Other historical events germane to this field were:
An early mention of the use of ultrasonics in medicine appears in, "Der Ultraschall in Der Medzin" by Verlog S. Hirzel, Zurich, 1949, mostly in diathermy work.
A direct demonstration of the technology of irrigation, aspiration and ultrasonics to effect cure was done by Soviet scientists working on cancer. The work obtained astonishing results whereby the ultrasound "seemingly" exhibited or prevented the growth of cancer cells in tumors. Not only that but the cells when transplanted failed to set-off cancer in the new host, i.e. the treated animal was not only healed but became immune. The Soviet research used "Liquidation Resolution" i.e. ultrasonic emulsification. This report was made in 1956 yet little work has been done in the U.S.A. mostly due to lack of equipment.
A rather interesting historical article appeared in "Ultrasonic News" of Dec. 1957 on "Ultrasound in Medicine". In the article it states that "thru years of usage by thousands of medical investigators and million of treatment of patients is has been established that over 3 watts per sq. cm or a total of 15 watts may be, in some manner, hazardous and that power below this level is always safe". In the same article excellent results using ultrasound are reported for contusions, distortions, inflammatory skin lesions, stomach ulcers, warts, leg ulcers and scleroderma as well as other diseases. This article also reports that over 3,000 medical papers on the use of ultrasound in medicine were published by 1956.
This same magazine (Ultrasonic News) in January 1958 P. 31 states "Hundreds are presently working in chemical research developing new techniques and methods of ultrasonic applications," and later, "In each of the medical specialties there is considerable investigation; particularly, specific studies in the field of urology, cardiology, and work on certain disorders of the eye and ear".
In May 1962 Topp & Eisenklam set forth the usage of ultrasonic high power for medical atomizers and one design used 40 Khz and 25 watts of input power and an injection through the center for the inlet of liquid for irrigation.
A little known use of the direct application of ultrasonics to tissue is in the treatment of the rare disease of laryngeal papillomatosis which is the only way to preserve life of the diseased victims (Birck & Manhart), (1963). The ultrasonic application is the only known cure.
The Acta Anaesth. Scandinavia, Vol. 8, 1964, P. 49 Herzog et al, reports the use of ultrasound for "Humidification of inspired gases via aerosols".
In the journal called "Ultrasonic", edition of July 1967, a complete description of a machine and probe for treatment of Meriere's disease is set forth. The work was done at Upsula, Sweden by S. J. Johnson. The author claiming usage for 5 years (back to 1958).
In "Ultrasonic, the Low and High Intensity Application" by Ensminger (Marcel Derker, Inc., N.Y.) 1975, Ensminger states on P. 143 under `Surgery`, that "There is very little equipment in the market for surgical use. Small hand held transducers are available for removing dental calculus. A similar instrument can be obtained for use in cataract surgery for emulsification and removing the fluid in the lens".
In Japan records from 400 A.D. are available and in fact the actual instruments of the Majima period of Japan are available for cataract work. This particular device consisted of a fine tubular needle which went into the soft cataract in the eye, and a suction tube attached to it which was sucked on by the mouth. The data and equipment are at the Nagoya University in Japan (Hurad).
This truly ancient application of cataract irrigation and aspiration was not duplicated in the West much before 1676-1743, by Brisseau (published in 1709). By 1755 Jacques Dairiel originated the full irrigation-aspiration surgical knife technique, followed by Graefe, with his famous, still in use, Graefe Knife in about 1860. As early as 1952 Fuchs made use of a two needle technique to simultaneously irrigate and aspirate during cataract removal.
The next advances in cataract surgery took place in several places at once: in Russia, Japan, England and the U.S., with the most concerted scientific attack being that of Y. Kuwahara and his associates in 1942 during the difficult war period and several years thereafter (until 1952). In 1952 Lavine et al, published "Effects of Ultrasonic Waves on the Refractive Media of the Eye" (Arch. Ophth. 47-204-1952), while at the same time Bergran, et al, in his "Ultrasonics and Their Scientific and Technical Application:" (Edward Buss, 3rd, Edition, Ann Arbor, 1942) pointed out the first early use of ultrasonics for medical work.
Examples herein of precedent devices clearly shows that the prior art used 1/2 wave vibrating stacks of nickel alloy material--the vibrations being created by the imposition of a high frequency magnetic field--to which has been attached a tool tip of one sort or another for doing surgical work. In most cases, the ultrasonic vibration was first laboriously created, and the knife, needle, saw, et al, was then "stuck-on", almost as an afterthought. The power was then applied and high frequency vibrations achieved--at only 2 to 10% efficiency. Thus, it is common practice to use 20 to 60 watts of instrument input power in dental scalers, when the job can be done with 10 watts or less and with far superior effectiveness if the device is designed as a system for effecting a specific task.
Even if prior inventors had fully recognized the need to make the tool element (i.e. the instrument used) part of the vibrating system, this would have usually been rendered impossible by the preexistant tools shape itself--which they insisted on using--the tool material chosen, or the operating length of the tool required to get ultrasonic energy into the work area; which did not match the ultrasonic requirements.
Thus, in the past too much compromise has been made in an effort to "make do", or to simply get any amount of ultrasound to work; with the result that most ultrasonic devices used in medical work are ineffective, inefficient and too difficult to use --when they work at all.
In the presentation of the invention which follows, we will show how devices can be evolved which will meet the criteria of the desired work problem uniquely; therefore, the object of this invention is to describe the complete electromechanical system, and its parts, and to show how to apply principles of ultrasonic design which are new and revealed herein for the first time.
In the "Fundamental Studies of Phaco-Emulsification" (Sect. VII: Y. Kuwahara, et al) the prevailing state of the ultrasonic medical art prior to our invention is epitomized in the drawing on Page 49 FIG. 38, however, this same approach is also shown in numerous texts on ultrasonic transducers, horns and tools of every sort and is here briefly shown, in FIGS. 1A and 1B.
In FIGS. 2A, B and C are shown an "idealization" of the "bent-needle" approach as visualized by Kuwahara and Associates. Note the assumption that the ultrasonic wave bends around the corner readily and the lack of any mismatch depictation at the joint; two conditions which are exactly never true.